Commit a8fcbd26 authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Add FIFO file names as alternative options to --control 



Enable the --control option to accept file names as an alternative to
file descriptors.

Example:

  $ mkfifo perf.control
  $ mkfifo perf.ack
  $ cat perf.ack &
  [1] 6808
  $ perf record --control fifo:perf.control,perf.ack -- sleep 300 &
  [2] 6810
  $ echo disable > perf.control
  $ Events disabled
  ack

  $ echo enable > perf.control
  $ Events enabled
  ack

  $ echo disable > perf.control
  $ Events disabled
  ack

  $ kill %2
  [ perf record: Woken up 4 times to write data ]
  $ [ perf record: Captured and wrote 0.018 MB perf.data (7 samples) ]

  [1]-  Done                    cat perf.ack
  [2]+  Terminated              perf record --control fifo:perf.control,perf.ack -- sleep 300
  $

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Acked-by: default avatarAlexey Budankov <alexey.budankov@linux.intel.com>
Acked-by: default avatarJiri Olsa <jolsa@redhat.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/20200902105707.11491-1-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 1f4390d8

tools/perf/Documentation/perf-record.txt

+2 −0
Original line number Diff line number Diff line
@@ -631,7 +631,9 @@ option. The -e option and this one can be mixed and matched. Events 
can be grouped using the {} notation.

endif::HAVE_LIBPFM[]



--control=fifo:ctl-fifo[,ack-fifo]::

--control=fd:ctl-fd[,ack-fd]::

ctl-fifo / ack-fifo are opened and used as ctl-fd / ack-fd as follows.

Listen on ctl-fd descriptor for command to control measurement ('enable': enable events,

'disable': disable events). Measurements can be started with events disabled using

--delay=-1 option. Optionally send control command completion ('ack\n') to ack-fd descriptor

tools/perf/Documentation/perf-stat.txt

+2 −0
Original line number Diff line number Diff line
@@ -180,7 +180,9 @@ with it. --append may be used here. Examples: 
     3>results  perf stat --log-fd 3          -- $cmd

     3>>results perf stat --log-fd 3 --append -- $cmd



--control=fifo:ctl-fifo[,ack-fifo]::

--control=fd:ctl-fd[,ack-fd]::

ctl-fifo / ack-fifo are opened and used as ctl-fd / ack-fd as follows.

Listen on ctl-fd descriptor for command to control measurement ('enable': enable events,

'disable': disable events). Measurements can be started with events disabled using

--delay=-1 option. Optionally send control command completion ('ack\n') to ack-fd descriptor

tools/perf/builtin-record.c

+26 −8
Original line number Diff line number Diff line
@@ -2236,7 +2236,17 @@ static int parse_control_option(const struct option *opt, 
{

	struct record_opts *opts = opt->value;



	return evlist__parse_control(str, &opts->ctl_fd, &opts->ctl_fd_ack);

	return evlist__parse_control(str, &opts->ctl_fd, &opts->ctl_fd_ack, &opts->ctl_fd_close);

}



static void close_control_option(struct record_opts *opts)

{

	if (opts->ctl_fd_close) {

		opts->ctl_fd_close = false;

		close(opts->ctl_fd);

		if (opts->ctl_fd_ack >= 0)

			close(opts->ctl_fd_ack);

	}

}



static void switch_output_size_warn(struct record *rec)
@@ -2578,9 +2588,10 @@ static struct option __record_options[] = { 
		"libpfm4 event selector. use 'perf list' to list available events",

		parse_libpfm_events_option),

#endif

	OPT_CALLBACK(0, "control", &record.opts, "fd:ctl-fd[,ack-fd]",

	OPT_CALLBACK(0, "control", &record.opts, "fd:ctl-fd[,ack-fd] or fifo:ctl-fifo[,ack-fifo]",

		     "Listen on ctl-fd descriptor for command to control measurement ('enable': enable events, 'disable': disable events).\n"

		     "\t\t\t  Optionally send control command completion ('ack\\n') to ack-fd descriptor.",

		     "\t\t\t  Optionally send control command completion ('ack\\n') to ack-fd descriptor.\n"

		     "\t\t\t  Alternatively, ctl-fifo / ack-fifo will be opened and used as ctl-fd / ack-fd.",

		      parse_control_option),

	OPT_END()

};
@@ -2653,12 +2664,14 @@ int cmd_record(int argc, const char **argv) 
	    !perf_can_record_switch_events()) {

		ui__error("kernel does not support recording context switch events\n");

		parse_options_usage(record_usage, record_options, "switch-events", 0);

		return -EINVAL;

		err = -EINVAL;

		goto out_opts;

	}



	if (switch_output_setup(rec)) {

		parse_options_usage(record_usage, record_options, "switch-output", 0);

		return -EINVAL;

		err = -EINVAL;

		goto out_opts;

	}



	if (rec->switch_output.time) {
@@ -2669,8 +2682,10 @@ int cmd_record(int argc, const char **argv) 
	if (rec->switch_output.num_files) {

		rec->switch_output.filenames = calloc(sizeof(char *),

						      rec->switch_output.num_files);

		if (!rec->switch_output.filenames)

			return -EINVAL;

		if (!rec->switch_output.filenames) {

			err = -EINVAL;

			goto out_opts;

		}

	}



	/*
@@ -2686,7 +2701,8 @@ int cmd_record(int argc, const char **argv) 
		rec->affinity_mask.bits = bitmap_alloc(rec->affinity_mask.nbits);

		if (!rec->affinity_mask.bits) {

			pr_err("Failed to allocate thread mask for %zd cpus\n", rec->affinity_mask.nbits);

			return -ENOMEM;

			err = -ENOMEM;

			goto out_opts;

		}

		pr_debug2("thread mask[%zd]: empty\n", rec->affinity_mask.nbits);

	}
@@ -2817,6 +2833,8 @@ int cmd_record(int argc, const char **argv) 
	evlist__delete(rec->evlist);

	symbol__exit();

	auxtrace_record__free(rec->itr);

out_opts:

	close_control_option(&rec->opts);

	return err;

}

tools/perf/builtin-stat.c

+15 −3
Original line number Diff line number Diff line
@@ -1047,7 +1047,17 @@ static int parse_control_option(const struct option *opt, 
{

	struct perf_stat_config *config = opt->value;



	return evlist__parse_control(str, &config->ctl_fd, &config->ctl_fd_ack);

	return evlist__parse_control(str, &config->ctl_fd, &config->ctl_fd_ack, &config->ctl_fd_close);

}



static void close_control_option(struct perf_stat_config *config)

{

	if (config->ctl_fd_close) {

		config->ctl_fd_close = false;

		close(config->ctl_fd);

		if (config->ctl_fd_ack >= 0)

			close(config->ctl_fd_ack);

	}

}



static struct option stat_options[] = {
@@ -1153,9 +1163,10 @@ static struct option stat_options[] = { 
		"libpfm4 event selector. use 'perf list' to list available events",

		parse_libpfm_events_option),

#endif

	OPT_CALLBACK(0, "control", &stat_config, "fd:ctl-fd[,ack-fd]",

	OPT_CALLBACK(0, "control", &stat_config, "fd:ctl-fd[,ack-fd] or fifo:ctl-fifo[,ack-fifo]",

		     "Listen on ctl-fd descriptor for command to control measurement ('enable': enable events, 'disable': disable events).\n"

		     "\t\t\t  Optionally send control command completion ('ack\\n') to ack-fd descriptor.",

		     "\t\t\t  Optionally send control command completion ('ack\\n') to ack-fd descriptor.\n"

		     "\t\t\t  Alternatively, ctl-fifo / ack-fifo will be opened and used as ctl-fd / ack-fd.",

		      parse_control_option),

	OPT_END()

};
@@ -2398,6 +2409,7 @@ int cmd_stat(int argc, const char **argv) 


	metricgroup__rblist_exit(&stat_config.metric_events);

	runtime_stat_delete(&stat_config);

	close_control_option(&stat_config);



	return status;

}

tools/perf/util/evlist.c

+53 −2
Original line number Diff line number Diff line
@@ -1727,12 +1727,63 @@ struct evsel *perf_evlist__reset_weak_group(struct evlist *evsel_list, 
	return leader;

}



int evlist__parse_control(const char *str, int *ctl_fd, int *ctl_fd_ack)

static int evlist__parse_control_fifo(const char *str, int *ctl_fd, int *ctl_fd_ack, bool *ctl_fd_close)

{

	char *s, *p;

	int ret = 0, fd;



	if (strncmp(str, "fifo:", 5))

		return -EINVAL;



	str += 5;

	if (!*str || *str == ',')

		return -EINVAL;



	s = strdup(str);

	if (!s)

		return -ENOMEM;



	p = strchr(s, ',');

	if (p)

		*p = '\0';



	/*

	 * O_RDWR avoids POLLHUPs which is necessary to allow the other

	 * end of a FIFO to be repeatedly opened and closed.

	 */

	fd = open(s, O_RDWR | O_NONBLOCK | O_CLOEXEC);

	if (fd < 0) {

		pr_err("Failed to open '%s'\n", s);

		ret = -errno;

		goto out_free;

	}

	*ctl_fd = fd;

	*ctl_fd_close = true;



	if (p && *++p) {

		/* O_RDWR | O_NONBLOCK means the other end need not be open */

		fd = open(p, O_RDWR | O_NONBLOCK | O_CLOEXEC);

		if (fd < 0) {

			pr_err("Failed to open '%s'\n", p);

			ret = -errno;

			goto out_free;

		}

		*ctl_fd_ack = fd;

	}



out_free:

	free(s);

	return ret;

}



int evlist__parse_control(const char *str, int *ctl_fd, int *ctl_fd_ack, bool *ctl_fd_close)

{

	char *comma = NULL, *endptr = NULL;



	*ctl_fd_close = false;



	if (strncmp(str, "fd:", 3))

		return -EINVAL;

		return evlist__parse_control_fifo(str, ctl_fd, ctl_fd_ack, ctl_fd_close);



	*ctl_fd = strtoul(&str[3], &endptr, 0);

	if (endptr == &str[3])